Rock drill



Oct. 14, 1941. E. G. GARTIN ROCK -DRILL Original Filed 001;. s, 1937' ,3 Sheets-Sheet l E. G. GARTIN ROCK DRILL v Oct. 14, 1941.

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Oct. 14, 1941. GART|N I 2,258,949

ROCK DRILL Original Filed Oct. 8, 1957 s Shets-Shee'b s Bay a 1g Fay/l. w 1/ g M HM W w 36' I I 39 9 ii m A U 1 y UNI t /(9 W M I li kmli WM,| M 0 1211 2702 I w r Z7420? 6; 6712 2522 MAW.

Patented Oct. 14, 1941 ROCK DRILL Elmer G. Gartin, Claremont, N. H., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application October 8, 1937, Serial No. 167,874 Renewed December I8, 1939 14 Claims.

This invention relates to rock drills, and more particularly to an improved automatic feeding means for a rock drill of the hammer type.

Automatic drill feeds operated and controlled by the vibrations set up within the drill hammer motor during the operation thereof, are well known in the art, and many forms thereof have been successfully operated in various parts of the country. In these devices, however, the con trol mechanism for the feed embodied relatively complicated reversible ratchet and pawl or intermittent grip devices and frictional resistance means for regulating the feed and controlling the direction of feed.

An object of the present invention is to provide an improved automatic drill feed wherein the operating and controlling mechanism for the feed is relatively simple in design, eliminating all relatively complicated ratchet and pawl or intermittent grip devices and frictional resistance means, while at the same time a positive and extremely reliable control is obtained. Another object is to provide an improved automatic feeding means for a. hammer rock drill whereby the feed is effected and controlled by a vibratory imparted to thelhammer motor by its hammer piston upon reversal of the hammer piston at the end of its stroke. A further object is to provide an improved automatic feeding means which utilizes the force of the jar resulting upon reversal of the hammer piston of the hammer motor for effecting feed of the hammer motor selectively in opposite directions. Another object is to provide an improved automatic feeding means for a hammer rockdrill wherein feed is automatically effected andcontrolled by vibrations set up within the hammer motor during operation of the latter, and having embodied therein improved means operable at will for effecting reversal of the direction of feed. A still further object is to provide an improved vibration controlled feed of the screw and nut type wherein improved means is provided to hold the screw and nut against relative rotation in one direction while .permitting free relative rotation in the opposite direction. Other objects and advantages of the invention will, however, hereinafter more fully appear.

In the accompanying drawings there are shown for purposes of illustration, two forms which the invention may assume in practice.

In these drawings,

Fig. l is a side elevationalview of a rock drill in which one illustrative form of the invention is incorporated.

Fig. 2 is a fragmentary planview of the rock drill shown in Fig. 1, with the drill hammer motor removed from itssupporting cradle.

Fig. 3 is an enlarged cross-sectional view taken substantially on line 3-3 of Fig. 2. I

Fig. 4 is an enlarged View in longitudinal vertical section taken substantially on line 4-4 of Fig. 2. i

Fig. 5 is a cross sectional view taken substantially on line 5-5 of Fig. 4, showing the control means in its reverse feed effecting position.

Fig. 6 is a view similar to Fig. 5, showing the control parts in forward feed effecting position.

Fig. 7 is a detail view of the control cam.

Fig. 8 is a view similar to Fig. 4, illustrating a modified form of construction.

Fig. 9 is a cross sectional view taken substantially on line 9-9 of Fig. 8.

Fig. 10 is a view similar to Fig. 9, showing the control parts in forward feed effecting position.

Fig. 11 is a view similar to Fig. 10, showing the control parts in reverse feed effecting position.

Fig. 12 is a detail view of the control member.

In both illustrative embodiments of the invention there is shown a hammer. rock drill of the mounted drifter type, comprising a guide shell I of a conventionaldesign having slidably guided thereon a rock drill2 of the pressure fluid actuated, reciprocatory hammer piston type. The rock drill is likewise of a conventional design, comprising a motor cylinder 3, having a piston chamber containing a reciprocatory hammer piston 4 for delivering impact blows to the shank of a usual drill steel 5, suitably supported within the forward end of the hammer motor cylinder. In this instance, the rock drill isattached to a cradle 6 having lateral guides l slidably received in parallel longitudinal guideways 8 formed on the guide shell.

Now referring to the preferred illustrated embodiment of the, invention shown in Figs. 1 to '7 inclusive, it will be noted that mounted on the guide shell I in longitudinal relation between the cradle guideways, is a feed screw l0, and this feed screw is suitably journaled for rotation on the guide shell within bearing yokes II, II and held in position on the guide shell by side bolts and spacing sleeves, in a conventional manner. The feed screw I'D, in this instance, may be manually rotated by means of a handle l2, connectible by a clutch l3 tothe feed screw, and this handle may he slid rearwardly out of clutched relation with the feed screw during automatic feed. A spring pressed plunger l4 mounted on the handle is engageable with spaced grooves l5 formed on the rearward extension [6 of the feed screw, for holding the handle in either of its positions.

Suitably fixed within a depending boss I! integral with the cradle 6 is a non-rotatable feed nut l8, having threads engaging the threads of the rotatable feed screw. This feed nut is cut away or slotted at I8 at its upper side, and projecting within this slot is a control member 29 in the form of a cam mounted for rotary motion ona longitudinal shaft 2!, supportedwithin-a bracket 22, secured to the rear end of the cradle. The bracket 22 also provides a support for the nonrotatable feed nut I8, in the manner shown in Fig. 4. This control member is received in a chamber 23 in the bracket and is formed with cam-like projections 24 shaped to conform to the contour of the threads of the feed screw but of slightly less cross'sectional area, so that when the control member is'rotated in one direction or the other the cam-like projections'th'ereon engag with a 'camming action the bottoms of certain 'of the screw threads, fora purpose to be later explained. 'Anupstanding projection 25 is formed integralwith the member 20 .and this projection is interposed between spring pressed plungers 26 guided within alined bores'formed in the bracket 22. When the cam member 2!] is in its central position shown in Fig. 3, the spring pressed plungers actto maintain the cam member wholly released'fromengagement with the feed screw .10. Extending between th plungers 25 isan eccentric 21, formed on a rotatable shaft 28 journaled'on the bracket and having an operating handle 29. When the'haridle 29 is turned to the left into the position'shown in "Fig. '5, one of the plungers 2ii is 'releasedfrom the camprojection 25 by the eccentric 21 while the other plunger acts on the projection of the cam 20 to rotate the latter to cause the bottoms of the camlike. projections thereon to engage the bottoms of certain of the threads'of'the feed screw ID to hold the latter against rotation'in one' direction, while permitting free rotation of the feed screw in the opposite direction, the plungeracting on the cam member yielding to permit movement of the cam member into its released position as the feed screw is rotated. As shown in Figs. 5 and 6, the cam member is arcuately slotted or grooved at 30 to provide clearance-forthe'plungers 26 to permit rotation of the cam'member relative to the plungers. When the cam member 20 is in the position shown in Fig. 5, the feed screw i0 is held against-rotation in a clockwise direction but isfree to rotate in a counter-clockwise direction, and-when the cam. member is in the position shown in'Fig. 6 the feed screw is held against rotation in a counter-clockwise direction while permitted to rotate freely in a clockwise direction.

In the modified form of construction shown in Figs. 8 to 12 inclusive, the feed screw and feed nut structure is the same as that described above in the preferred embodiment of the invention. In this instance, however, a control member is threadedly connected at 36 to a longitudinal screw 3'! formed on a shaft 38, secured within 7 the cradle bracket. This control member is formed with projections 39 shaped to conform to the shape of the screw threads, but of slightly less cross-sectional ar'eathan the spaces between the screw threads, so that'a slight endwise movement of the control member relative to the feed screw is possible. In Fig. 8, the clearance spaces between the projections 39 and the screw threads are exaggerated for illustrative Purposes, and in actual practice these clearance spaces will be relatively slight. As in the form of the invention above described, the control member 35 is provided with an upstanding projection GE, interposed between spring-pressed plungers 4 I, guided within alined bores formed within th cradle bracket, and a similar eccentric 42 isarranged between the plungers and engageable with the latter for releasing one or the other of the plungers from the control member, thereby to enable the other plunger to act on the projection on the control member to rotate the latter relative to the screw 31. As in the form of the invention above described, the eccentric is formed on a shaft provided with an operating handle M. Rotation of the control member 35 relative to the screw 31 causes the control member to move axially to bring the projections thereon into-frictional camming engagement with the sides of certain of the screw threads, thereby to bind frictionally the feed screw against rotation in one direction while permitting free rotation of the feed screw in the opposite direction, the springpressed plunger acting'on the control member yielding topermit movement of the control member into its released position when the feed screw is rotated. The control member is arcuately slotted or grooved ati5 to provide clearance for the plungers 4| to permit rotation and axial movement of the control member relative to the plungers. When the eccentric operating handle is turned into its position shown in Fig. 10, the control member is moved into a position to hold the feed screw against rotation in a counterclockwise direction as viewed in Fig. 10 while permitting free rotation of the feed screw in a clockwise direction, and when the eccentric operating handle is turned into its opposite position as shown in Fig. 11, the feed screw is held against rotation in a clockwise direction as viewed in Fig. 11, while permitted to rotate freely in a counter-clockwise direction.

The general mode of operation of both forms of the invention will be clearly apparent from the description given. When it is desired to effect feed of the drilling motorforwardly along the shell guideways the operator manipulates the control handle of the control mechanism to rotate the control member into its forward feed effecting position, thereby to cause the cam projections thereon to bind frictionally with the feed screw at the bottoms or sides of certain of the screw threads while permitting free rotation of the screw relative to the cam member and feed nut in a forward feeding direction. Pressure fluid is then supplied in the usual manner to the drilling motor to effect reciprocation of the hammer piston to actuate percussively the drill steel. The reciprocation of the hammer piston causes, due to the sudden reversal of movement of the hammer piston within its cylinder, vibration or recoil movement in a longitudinal direction of the hammer motor, as is well understood by those skilled in the art. The movement of the hammer motor in a rearward direction with respect to the shell guideways is checked automatically by the frictional engagement of the cam member with the threads of the feed screw, while forward movement of the hammer motor is unimpeded since the feed screw is free to rotate relative to the cam member and feed nut in a direction to permit forward feed. The action of the hammer piston as the latter rapidly reciprocates within its cylinder to effect percussive actuation of the drill'steel, causes the cam member to rotate into a position to permit forward feed of the drill with respect to the guide shell, the cam member automatically engaging.

the threads of the feed screw to prevent reverse rotation of the feed screw while permitting free rotation of the feed screw in the forward feed direction. When it is desired to effect reverse feed of the hammer motor along the shell guideways the cam member is moved into its opposite position with the cam projections thereon frictionally engaging the threads of the feed screw in the opposite direction. When the parts are in this reverse feed effecting position, the direction of feed is automatically reversed, since the cam member at that time permits free rotation of the feed screw in a reverse feed effecting direction to permit movement of the rock drill in a reverse direction along the guide shell while the cam member automatically checks rotation of the feed screw in the forward feed direction. When the cam member is rotated into its intermediate neutral position with the cam projections thereon out of engagement with the threads of the feed screw, the automatic feed is, of course, interrupted, it then being possible manually to slide the drill along the shell guideways in either direction as desired, by means of the handle 12. In both embodiments of the invention, by varying the position of the eccentric operating handle the pressure of frictional contact between the control member and the feed screw may be regulated, thereby to enable regulation of the rate of feed in either of opposite directions.

As a result of this invention it will be noted that an improved automatic feeding means is provided for a hammer rock drill whereby the jars effected by the reciprocatory hammer piston of the hammer motor are utilized to effect feed of the drill in an improved manner. It will further be evident that by the provision of the improved control means for the automatic feeding means, all relatively complicated ratchet and pawl or intermittent grip devices and frictional resistance means are eliminated, thereby resulting not only in an increased life of the feed control parts, but also a decrease in the cost of manufacture and replacement. It will still further be evident that an improved automatic vibration controlled drill feed is provided which is relatively simple and rugged in design and well adapted to withstand the severe conditions of service encountered in the drilling of rock. These and other uses and advantages of the improved drill feeding means will be clearly apparent to those skilled in the art.

While there are in this application specifically described two forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a rock drill feeding means, the combinaprising frictional control means automatically operative to prevent movement of said motor along said guide shell in one direction while permitting free movement of said motor in the opposite direction, said control means comprising relatively rotatable threadedly engaged members and a rotatable cam frictionally engageable with the threads of one of said members to prevent relative rotation therebetween in one direction while permitting free relative rotation in the opposite direction.

2. In a rock drill feeding means, the combination with a hammer motor within which longitudinal vibrations occur during the operation thereof and a guide shell on which said motor is slidably guided, of a feed screw element mounted on said shell and a feed nut element carried by said motor and engaging said screw element, said screw and nut elements being relatively rotatable, and stop means for frictionally engaging with a camming action certain of the threads of one of said screwand nut elements for preventing relative rotation therebetween in one direction while permitting free relative rotation in the opposite direction.

3. Ir'1 a rock drill feeding means, the'combination with a hammer motor within which longitudinal vibrations occur during the operation thereof and a guide shell on which said motor is slidably guided, of a feed screw element mounted onsaid shell and a feed nut element carried by said motor and engaging said screw element, said screw and nut elements being relatively rotatable, and stop means for frictionally engaging with a camming action certain of the threads of one of said screw and nut elements for preventing relative rotation thereebetween in one direction while permitting free relative rotation in the opposite direction, said stop means comprising a cam member rotatable on an axis parallel to the longitudinal axis of said feed screw element.

4. In a rock drill feeding means, the combination with a drilling motor'within which longitudinal vibrations occur during the operation thereof, of automatic feeding mechanism for the drilling motor controlled by the vibratory action of the latter and comprising relatively rotatable screw and nut elements and means frictionally engaging the threads of one of said elements for holding the latter against relative rotation in one direction while permitting free relative rotation thereof in the opposite direction.

5. In a rock drill feeding means, the combination with a drilling motor within which longitudinal vibrations occur during the operation thereof, of an automatic feeding mechanism for the feeding motor controlled by the vibratory action of the latter and comprising a feed screw journaled for rotation on an axis parallel to the path of movement of said drilling motor during the feeding thereof, a non-rotatable feed nut mounted to move with the drilling motor and engaging said feed screw, and means mounted to move with the drilling motor and associated with said feed nut for frictionally binding said feed screw against rotation in one direction while permitting free rotation of said feed screw in the opposite direction. v a

6. In a'feeding device, the combination with a hammer motor and a support whereon said motor is slidably guided, said hammer motor comprising a reciprocatory'hammer piston imparting jars to the hammer motor tending to move said motor longitudinally on said support, of feed control means comprising a pair of relatively rotatable members in threaded engagement with each other and one of which members is adapted to be rotated by said motor upon movement of the latter on said-support and controlling means for controlling the direction of rotation of said rotatable member'to enable said motor to be advanced with respect to said support by the jars imparted thereto by the hammer piston, said controlling means comprising a control member frictionally engageable with the threads of said rotatable member.

'7. In-a feeding device, the combination with a hammer motor and a support whereon said motor is slidably guided, said hammer motor comprising a reciprocatory hammer piston imparting jars to the hammer motor tending to move said motor longitudinally on said support, of feed control means comprising a pair of relatively rotatable members in threaded engagement with each other and one of which members is adapted to be rotated by said motor upon movement of the latter on said support and controlling means for controlling the direction of rotation of said rotatable member to enable said motor to be advanced with respect to said support by the jars imparted thereto by the hammer piston, said controlling means comprising a control'member frictionally engageable with-the threads of said rotatable member, and yieldable means for urging said control member into frictional engagement with said rotatable member to hold the latter against rotation in one direction and automatically yieldable to permit free rotation of said rotatable member in the opposite direction.

'8. Ina rock drill feeding means, the combination with a hammer motor within which longitudinal vibrations occur during the operation thereof and a guide on which said motor is guided, of control means for effecting feeding of the motor along said guide comprising a feed screw journaled on said guide, a non-rotatable feed nut carried by said motor and engaging said feed screw, and means associated with said feed nut for checking rotation of said screw in one direction while permitting free rotation thereof in the opposite direction comprising a control member movable axially relative to said nut to effect frictional engagement with the sides of certain of the threads of said screw.

9. In a rock drill feeding means, the combination with a hammer motor within which longitudinal vibrations occur during the operation thereof and a guide on which said motor is guided, of control means for effecting feeding of the motor along said guide comprising a feed screw journaled onsaid guide, a non-rotatable feed nut carried by said motor and engaging said feed screw, and means associated with said feed nut for checking rotation of said screw in one direction while permitting free rotation thereof in the opposite direction comprising a control member movable'axiall'y relative to said nut to effect frictional engagement with the sides of certain of the threads 'of'said screw, and'means for rotating said control member to effect such axial movement thereof.

10. In a rock drill feeding means, the combination with a hammer motorwithin which longitudinal vibrations occur during the operation thereof and a guide shell having a guideway on which said motor is guided for feeding movement longitudinally therealong, of means for controlling the feeding movement of said ham- "mer motor along saidguide-shell-guideway comprising relatively rotatable, mechanically interengaging control members, one of said'members extending longitudinally of said guide shell in parallelism with the guideway thereof, frictional control means cooperating with said members and frictionally controlling, by direct frictional contact with the interengaging portion of saic longitudinally-extending member, relative rotation of said members, thereby automatically to prevent movement of said hammer motor along said shell guideway in one direction while permitting free movement of said motor in the opposite direction, and manual control means operable at will for reversing the relation of said frictional control means with respect to said longitudinally-extending control member whereby the direction of feed may be reversed.

11. In a rock drill feeding means, the combination with a hammer motor within which longitudinal vibrations'occur during the operation thereof and a guide shell on which said hammer motor is mounted for feeding movement longi tudinally therealong, of means for controlling the feeding movement of said hammer motor along said guide shell comprising frictional control'means automatically operative to preclude movement of said motor along the guide shell in one direction while permitting free movement of the motor therealong in the opposite direction, said controlling means including relatively rotatable, interengaging control members having their axes of relative rotation extending longitudinally of said guide shell in parallelism with the path of movement of the hammer motor therealong, a rotatable cam frictionally engageable directly with the interengaging portion of one of said members to prevent relative rotation between said members in one direction while permitting free relative rotation thereof in the other direction, and manual control means for said cam whereby the latter may be released from frictional engagement with or its relation relative to said control member may be changed whereby the feed may be interrupted or its direction reversed at will.

12. In a rock drill feeding means, the combination with a drilling motor within which longitudinal vibrations occur during the operation thereof, of an automatic feeding mechanism for said drilling motor controlled by the vibratory action of the latter comprising relatively rotatable, interengaging control elements, the rotatable one of said elements arranged with its axis of rotation extending longitudinally in parallelism with the path of feeding movement of said hammer motor, and means directly frictionall engaging the interengaging portion of said longitudinally extending rotatable element at points in adjacency to the points of interengagement of said elements, for holding the element directly frictionally engaged thereby against rotation relative to the other element in one direction while permitting free relative rotation in the opposite direction.

13. In a rock drill feeding means, the combination with a hammer motor within which longitudinal vibrations occur during the operation thereof, of automatic feeding mechanism for said hammer motor controlled by the vibratory action of the latter comprising cooperating relatively rotatable feed controlling elements having interengaging projections thereon, the rotatable one of said elements arranged with its axis of rotation extending longitudinally in parallelism with the path of feeding movement of said hammer motor, means frictionally engaging the projections on said longitudinally extending rotatable element for holding the latter against rotation in one direction relative to the other element while permitting free relative rotation thereof in the opposite direction, and means operable at will for reversing the position of said frictional means with respect to said rotatable controlling element whereby the direction of feed may be reversed.

14. In a rock drill feeding means, the combination with a hammer motor within which longitudinal vibrations occur during the operation thereof, of automatic feeding mechanism for said hammer motor controlled by the vibratory action of the latter comprising relatively rotatable screw and nut feed controlling elements, one mounted to move with the hammer motor and the other remaining stationary as regards bodily movement during feeding movement of the hammer motor, means associated with said screw and nut elements and directly frictionally engaging the threaded portion of one of said elements for frictionally binding said element against rotation in one direction while permitting free rotation thereof in the opposite direction, and means operable at will for releasing said frictional means from engagement with or for changing the position of said frictional means with respect to said rotatable controlling element whereby the feed may be interrupted or the direction of feed reversed.

ELMER G. GARTIN. 

